Effects of Abrocitinib Treatment on Skin Barrier Function

Prior treatment

• Concurrent enrolment in another clinical trial where the subject is receiving an IMP or participation in another clinical trial with investigational product during the last 30 days before inclusion or 7 half-lives of previously used trial medication, whichever is longer.
• Having used systemic immunosuppressive/immunomodulating therapy (e.g. systemic corticoster-oids methotrexate, cyclosporine, azathioprine, mycophenolate mofetil, JAK inhibitors) or tanning beds or phototherapy during any week within the 4 weeks or receipt of any marketed biologic ther-apy (e.g., dupilumab, tralokinumab) within 3 months or 5 half-lives, whichever is longer, prior to baseline
• Treatment of selected marker skin areas (non-lesional skin at volar forearm and extensor forearm, lesional skin) with topical corticosteroid or topical calcineurin inhibitor 1 week prior to baseline visit and throughout the study.
• Treatment of skin areas of examination with emollients 24 hours prior to baseline visit and throughout the study.

Other illness

• Active dermatologic conditions that may confound the diagnosis of AD or would interfere with as-sessment of treatment, such as scabies, cutaneous lymphoma, or psoriasis.
• Known active allergic or irritant contact dermatitis that is likely to interfere with the assessment of severity of AD.

Other

• 1\. Subject is unable to provide written informed consent or comply with the protocol
• Involvement in the planning and/or conduct of the study.

• Written informed consent obtained from the subject prior to performing any protocol-related pro-cedures, including screening evaluations
• Age ≥ 18 years at time of study entry.
• Diagnosis of chronic atopic dermatitis for at least 1 year prior to enrollment based on American Academy Criteria
• Eczema Area and Severity Index (EASI) score ≥12 at baseline visit (Week 0)
• Investigator Global Assessment (IGA) ≥3 at baseline visit (Week 0)
• Subject is willing and able to comply with the protocol for the duration of the study
• Subject receives abrocitinib by the treating dermatologist within routine care